عنوان مقاله [English]
The present paper attempts to investigate the seismic performance of four different irregular RC structures having 10 and 15 stories and with two different plan configurations. These structural models are irregular both in plan and height. With respect to the complexity of the irregular structures’ behavior during earthquakes and regarding the building codes requirements, linear and non-linear static analyses as well as linear and non-linear dynamic analyses have been performed for seismic design and evaluation of structural models. First using nonlinear analysis methods the seismic performance of the original frames were evaluated. Subsequently, the irregular structures were reinforced with steel braces in X and zigzag configurations and their performance levels were determined after the rehabilitation. The comparison between the results obtained from the analyses of the initial structures and the retrofitted models indicated that employing both types of steel braces, X and zigzag configurations, can lead to significant improvement in seismic performance level of the structures. The results also indicated that the seismic performance of models studied having simultaneous irregularities in plan and height was satisfactory. However, it was observed that the irregularity in plan can adversely affect the soft story condition. Therefore, it seems that more research should be conducted on seismic performance of buildings with combinations of different types of irregularity and the code provisions should be improved to include these effects in analysis and design.